That’s the headline. The article says that growing crops absorb CO2 and reduce it in the atmosphere and dying or harvested crops release CO2 back into the atmosphere. Back when schools used to teach stuff it was in the science book.
You need to read the first paragraph of the article again. The headline accurately reflects the article’s lede.
1st sentence - CO2 levels INCREASE during growing season
2nd sentence - they INCREASE again when plants release their CO2